How to stop --- if space is pressed twice, a full-stop gets appeared automatically --- IOS

Replace " . " with space ----- if space is pressed twice, a full-stop gets appeared automatically ---- IOS

if ( (range.location > 0 && [string length] > 0 &&
          [[NSCharacterSet whitespaceCharacterSet] characterIsMember:[string characterAtIndex:0]] &&
          [[NSCharacterSet whitespaceCharacterSet] characterIsMember:[[textField text] characterAtIndex:range.location - 1]]) )
    {
        //Manually replace the space with your own space, programmatically
        textField.text = [textField.text stringByReplacingCharactersInRange:range withString:@" "];

        //Tell Cocoa not to insert its space, because you've just inserted your own
        return NO;
    }



//User not enter after 1st space in UITextField --- ios

return !(range.location > 0 &&
             [string length] > 0 &&
             [[NSCharacterSet whitespaceCharacterSet] characterIsMember:[string characterAtIndex:0]] &&
             [[NSCharacterSet whitespaceCharacterSet] characterIsMember:[[textField text] characterAtIndex:range.location - 1]]);